Shocked neighbours, standing beyond the police tape, stared at the house. Friends gathered at the scene, too, and held one another and cried.

Hours later, about 1am on Easter Monday, Charles Mihayo was charged with two counts of murder, and remanded to appear in the Melbourne Magistrates Court on Tuesday.

As light broke on the street, more mourners began arriving - roughly one an hour - to offer some sort of tribute.

A woman walking a small dog and a young boy riding a bike dropped off a tiny bunch of white and orange flowers.

A small girl and an older man walked up to the white fence, and placed their own vibrant pink bouquet just outside the house before walking quietly away.

Strangers came, like Helen Temple of Watsonia - a mother who fought back tears while leaving a single flower for two children she never met. "I heard it on the news, and just thought to put a flower for the girls," she said. "I have daughters, too, and it's so sad. Hope they rest in peace, poor things."

Some family members arrived around 9.30am and were ushered into the home by police. At 10.15am, the deceased estate cleaners arrived to perform their grave duty and clean up the crime scene.

Gary Lurati, a friend of the girls' mother, said he was in shock about what had happened. Mr Lurati met her two years ago.

By that time, she had split up with Mr Mihayo, he said, and was focused solely on her two daughters and their welfare.

"I just can't believe it," Mr Lurati said. "She's always talking about her kids. She's always doting on them. They were like the apple of her eye."

He said she was working full time, and the two children had to be put in childcare every day. They weren't yet old enough for school.

"It's a terrible thing that's happened. She's such a nice girl," he said. "I can't get it out of my mind."